The Castle of the Heights, as Cashtal yn Ard means in Manx, is not a Castle
at all but the remains of one of the largest Neolithic Long Barrows in Britain,
and the largest by far on Man.

It dates from around 2000 BC and like all Long Barrows would once have been
covered by a large earthwork. It is of a fairly simple design with
5 main chambers arranged in a straight line and a large 'forecourt'. The
whole structure was originally up to 120 feet long and 45 feet wide.

The name "Cashtal" has been applied to several miscellaneous structures on
the Island none of which are really Castles, but Cashtal yn Ard is impressive
in its antiquity and also its setting with some superb views across the flat
north of the island towards the mountainous centre.